EMS-ESP32/interface/src/utils/usePersistState.ts

import { useEffect, useMemo, useState } from 'react';

export const usePersistState = <T>(
  initial_value: T,
  id: string
): [T, (new_state: T) => void] => {
  // Set initial value
  const _initial_value = useMemo(() => {
    const local_storage_value_str = localStorage.getItem('state:' + id);
    // If there is a value stored in localStorage, use that
    if (local_storage_value_str) {
      return JSON.parse(local_storage_value_str);
    }
    // Otherwise use initial_value that was passed to the function
    return initial_value;
  }, []);

  const [state, setState] = useState(_initial_value);

  useEffect(() => {
    const state_str = JSON.stringify(state); // Stringified state
    localStorage.setItem('state:' + id, state_str); // Set stringified state as item in localStorage
  }, [state]);

  return [state, setState];
};